Redirection to a strange file descriptor no.

Question

I came across a working ksh script [interactive] today, where I saw the below statement.

printf "Enter the release no. : " >&5

I wonder the use of ">&5" when the author could have as well use nothing or say ">&1".

Can someone shed some light on this point?

Thanks in advance

-- Benil

Answer 1

He probably has remapped the file descriptors or does use the file descriptor 5 for something special

e.g. to only temporarily redirect errors to /dev/null

#errors produced here go to stderr
....
#now save stderr to fd 5
exec 5>&2
#redirect to /dev/null
exec 2>/dev/null
...
# do stuff which errors are discarded
......
# restore stderr from fd 5
exec 2>&5

So check more of the script what it does before